At the time of the first trimester screening, namely between 11+0 and 13+6 weeks of pregnancy, you have probably known for a few days or weeks that you are pregnant. Your gynecologist has informed you about all important examinations and you are now asking yourself what you and your partner want or should claim from all the possible screening and diagnostic procedures.
What are the sensible examinations for you?
First of all, you should ask yourself the following question:
What do you want to know and why?
How would a possible child’s disability affect your life and that of your family?
Can you imagine the life with a special child?
If your answered the last question with a clear “yes”, “not wanting to know” is also an option for you. If necessary, you decide in this case f.e. In the second trimester only for a differentiated diagnostic in order to find out whether there are any abnormalities in your child for the upcoming birth, that might make your decision for a specific maternity clinic seem sensible. (E.g. a perinatal center with attached pediatric surgery, -orthopedics, -nephrology, -heart center)
But even in the case just described, very early diagnosis can help the child or the children in your womb, should e.g. fetal surgery improves the situation and the chance of a healthy life. But more about that later.
Most parents want to get an ultrasound examination very early on because they are insecure. The jungle of possibilities and eventualities seems impenetrable? You cannot answer any questions at all, have a high security need? Surely don’t want to make a wrong decision?
The ultrasound initially provides the basis for recording the development of the fetus. In the first trimester screening, possible abnormalities, so-called markers, are recorded in the above-mentioned interval between the 12th and 14th week of pregnancy. The individual risk for them is then calculated using the weighting of the ultrasound sign listed below in a sophisticated algorithm:
- nuchal translucency NT
- nasal bone NB
- ductus venosus DV
- tricuspid valve in the heart TI (Trikuspidalinsuffizienz)
- maternal age
- hormone levels in the mother`s blood (Biochemestry)
- morphological abnormalities,
- the supply of the fetus via the placenta
This is a probability calculation which, depending on the qualification and certification of the doctors, can be a forecast of 92-95%. If only the neck of the fetus is measured, the statistical predictive value is significantly lower.
Eliminating the combined blood test for the hormones PPP-A and ß-HOG reduces the overall probability of prediction by approx. 3%.
Examination between the 12th and the 14th week of pregnancy is extremely important, since markers such as a thickened neck or the above-mentioned other abnormalities disappear after the 15th week of pregnancy. They are not malformations in themselves, they only point to such possible striking findings, e.g.
chromoson disorders, heart defects, syndromic diseases.
We will not leave you alone with the results of this investigation. It is important to us that you understand the scope of the respective findings and its consequences.
From an individual risk of 1:100 or worse, we recommend performing invasive diagnostics if you with to clarify the situation with advanced diagnostics. A non-invasive prenatal test is not indicated in the case of conspicuous markers in first trimester screening, since (with thickened NT) around 12-19% of possible chromisomal defects/ syndromic diseases are not recognized.
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